JP2757481B2 - Electronically controlled antenna device - Google Patents

Description

The present invention relates to an electronically controlled antenna device capable of variably controlling directivity characteristics.

B. Prior Art With the remarkable development of telecommunications and the development of the information society, various forms of communication have been diversified, and one of them is mobile communication. This is used for business use such as ships, airplanes, taxis, etc., as well as for personal use car phones, personal radios, etc. In recent years, car phones, personal radios and radio facsimile capable of more advanced information transmission. Such is desired.

In such mobile radio communication, the biggest obstacle is multipath fading (multipath fading). As a method for improving the quality of a received wave by compensating or reducing the fading, there are a diversity receiving method in which a plurality of antennas are switched according to a radio wave state, and an adaptive antenna for combining a plurality of received signals.

FIG. 7 is a configuration diagram of a conventional variable control antenna in which a plurality of antenna elements and circuit elements are combined and the directional characteristics of the antenna are controlled by a received wave.

In FIG. 7, 1a to 1d are antenna elements, 2a to 2d are high-frequency receiving circuits connected to the respective antenna elements 1a to 1d, and 3 is a combiner that combines received signals output from the high-frequency receiving circuits 2a to 2d. Reference numeral 4 denotes a demodulation circuit for demodulating the reception signal synthesized by the synthesizer 3 and reference numeral 5 denotes a reception state sensor for detecting a reception state from the output of the demodulation circuit 4. The output signal of the reception state sensor 5 is supplied to the synthesizer 3. Feedback is provided.

In the variable directional antenna configured as described above, an incoming radio wave induces a voltage in each of the antenna elements 1a to 1d and a high-frequency current flows, and the high-frequency current flows into each of the high-frequency receiving circuits 2a to 2d. And
After the high frequency signal of the predetermined frequency selected by the high frequency receiving circuits 2a to 2d is frequency-converted into an intermediate frequency signal and amplified,
The signal is input to the combiner 3 and combined so as to be in an optimal reception state. The synthesized signal is demodulated by the demodulation circuit 4 and output to a telephone or the like (not shown).

On the other hand, the output signal of the demodulation circuit 4 is input to the reception state sensor 5, and the reception state combined by the combiner 3 is detected, and the detection result is fed back to the combiner 3.
Signals received by the high-frequency receiving circuits 2a to 2d through the antenna elements 1a to 1d are combined so as to be in an optimum receiving state to obtain a desired directivity.

C. Problems to be Solved by the Invention However, in the antenna with the variable directivity as described above, the signals received by the plurality of antenna elements 1a to 1d and the corresponding high-frequency reception circuits 2a to 2d are combined to obtain a desired signal. Since this is a method for obtaining directivity, a plurality of antenna elements 1a to 1d
A large space is required to install the antenna, which is not suitable for a moving body such as an automobile, and the cable wiring for connecting the antenna element and the high-frequency receiving circuit (or the transmitting circuit) becomes complicated. Multiple antenna elements and multiple high-frequency receiving circuits (or transmitting circuits)
However, there is a problem that the cost increases.

An object of the present invention is to provide an electronically controlled antenna device that can variably control directivity with a single antenna element.

D. Means for Solving the Problems The present invention will be described with reference to FIG. 1 showing an embodiment. The variable directivity type electronically controlled antenna device according to the present invention comprises a base plate 11 and a A plurality of patch plate conductors 12a to 12h arranged in parallel, and an insulator 13 that is interposed between the ground plate 11 and the plurality of patch plate conductors 12a to 12b, and whose permittivity or magnetic permeability in a high frequency region changes by an electromagnetic field, Control means 18 variably controls the directivity by changing the distribution of the electromagnetic field applied to the insulator 13 via the base plate 11 and the patch plate conductors 12a to 12h.

E. Action When a DC or low-frequency electromagnetic field is applied to each of the patch plate conductors 12a to 12h from the control means 18 to the insulator 13 sandwiched between the ground plate 11 and the patch plate conductors 12a to 12h, The dielectric constant or the magnetic permeability of the insulator 13 changes. Therefore, by adjusting the electromagnetic field passing through each of the patch plate conductors 12a to 12h, the directivity of the antenna changes. That is, if the electromagnetic field passing through each patch plate conductor is variously adjusted according to the radio wave condition, a single antenna can be controlled to have a directional characteristic suitable for reception or transmission.

In the above sections D and E for describing the configuration of the present invention, the drawings of the embodiments are used for easy understanding of the present invention, but the present invention is not limited to the embodiments.

F. Examples Hereinafter, examples of the present invention will be described with reference to the drawings.

1 to 3 show an embodiment of a variable directivity type electronically controlled antenna device according to the present invention. FIG. 1 is an overall configuration diagram, FIG. 2 is a plan view of an antenna element, and FIG. Is a sectional view thereof.

In FIG. 1, reference numeral 10 denotes a flat plate-shaped antenna element capable of variably controlling the directivity. This antenna element 10 is separated from a ground plane 11 by a desired distance as shown in FIGS. A plurality of fan-shaped patch plate conductors 12a to 12h opposed in parallel and arranged in a disk shape, and a high-frequency relative dielectric constant caused by an electromagnetic field interposed between the ground plate 11 and the patch plate conductors 12a to 12h in a sandwich shape. An insulator whose liquid crystal changes, for example, a liquid crystal dielectric 13 is provided. Further, the short pin 14 reaching the ground plane 11 from the center of the patch plate conductors 12a to 12h and the DC cut-off capacitor 15 interposed in series with the short pin 14, and slightly offset from the center of the patch plate conductors 12a to 12h to the outer peripheral side. A power supply pin 16 is provided at a position, and a power supply coaxial cable 17 is connected to the power supply pin 16. As apparent from FIG. 3, the short pins 14 are connected to the patch plate conductors 12a to 12h.
Apart from the
14 and the patch plate conductors 12a to 12h conduct at high frequencies and are separated at direct current.

Further, each patch plate conductor 12 of the antenna element 10 having the above configuration
As shown in FIG. 1, a direct current bias voltage (or a low frequency voltage) can be supplied from the direct current bias control circuit 18 to each of the patch plate conductors between a to 12h and the ground plane 11.
The combination of the DC bias voltage applied from the DC bias control circuit 18 to the antenna element 10
Ten directivities are variably controlled. In FIG. 3, the signal line of the DC bias voltage is not shown.

The feed coaxial cable 17 connected to the antenna element 10 has
As shown in FIG. 1, a high-frequency receiving circuit 19 similar to the conventional one is connected, and a demodulation circuit 20 for demodulating a received signal is connected to an output side of the high-frequency receiving circuit 19. The reception state sensor 21 detects the reception state from the output of the demodulation circuit 20 and feeds back the detection result to the DC bias control circuit 18.

Next, the operation of the present embodiment configured as described above will be described.

First, when a DC bias voltage of a combination set according to the tuning frequency of the high-frequency receiving circuit 19 is applied between the ground plane 11 of the antenna element 10 and each of the patch plate conductors 12a to 12h, the presence or absence of the DC bias voltage High-frequency relative permittivity ε of the liquid crystal dielectric 13 facing each of the patch plate conductors 12a to 12h according to
r changes, and the antenna element 10
Also changes its directivity.

FIG. 4 schematically shows the behavior of the liquid crystal molecule arrangement that changes according to the state of the DC bias voltage applied to the liquid crystal dielectric 13.

FIG. 4 (a) shows a case where the DC bias voltage is zero. At this time, the arrangement of the liquid crystal molecules 13a in the liquid crystal dielectric 13 is in a random non-directional state, and the high-frequency relative permittivity εr is the largest. FIG. 4 (b) shows an alignment state when a small DC bias voltage is applied, and liquid crystal molecules 13b whose longitudinal direction is aligned at right angles to the electrode and liquid crystal molecules 13c which are not aligned are mixed. And the high-frequency relative permittivity εr becomes smaller than that in the case of no electric field. FIG. 4 (c) shows the state of the molecular arrangement when the DC bias voltage is maximized. All the liquid crystal molecules 13a are aligned at right angles to the electrodes, and the high-frequency relative permittivity εr is the smallest. Become.

FIG. 5 is a characteristic diagram showing a state in which the high-frequency relative permittivity εr of the liquid crystal dielectric 13 changes according to the DC bias voltage.

When the high-frequency relative permittivity εr of the liquid crystal dielectric 13 corresponding to each of the patch plate conductors 12a to 12h changes in this manner, the entire antenna element 10 has a variable directivity having a dielectric having a different relative permittivity depending on the direction. It becomes an antenna.

Therefore, the result detected by the reception state sensor 21 is fed back to the DC bias control circuit 18 to
By automatically combining and selecting the DC bias voltage applied to each of the 10 patch plate conductors 12a to 12h according to the surrounding radio wave condition, it is possible to obtain an antenna having directivity suitable for the receiving condition, Good reception without fading becomes possible. In addition, since the antenna element 10 is a single unit, the antenna element 10 can be easily mounted on a car, and can be installed in a small space and at low cost.

FIG. 6 is a cross-sectional view of an insulator showing another embodiment of the present invention.

2 and FIG. 3 is different from FIG. 2 and FIG. 3 in that an insulator 32 mixed with a resin microcapsule 31 in which a liquid crystal substance 30 is sealed is replaced with a patch plate conductor 12a-12h. It is provided in a sandwich shape between the main plates 11.

Liquid crystal substance 31 encapsulated in resin microcapsules 31
Is much more stable than a normal liquid crystal encapsulation method, and is less susceptible to external pressure and temperature, thereby increasing the reliability of the antenna. By adjusting the amount of the resin microcapsules 31 mixed in the insulator 32, there is an advantage that desired variable dielectric characteristics can be obtained.

Although only the receiving antenna has been described in the above embodiment, the present invention can be applied to the transmitting antenna according to the same principle. In addition, the antenna described in the above embodiment can be effectively used as an antenna for a mobile body other than a car or an antenna for a fixed station where a mounting space is limited. Furthermore, an optical crystal or an opto-ceramic can be used as the insulator. Furthermore, the shape and arrangement pattern of the patch plate conductors constituting the antenna element are not limited to those of the above-described embodiment.

G. Effects of the Invention As described above, according to the present invention, between a ground plate and a plurality of patch plate conductors arranged to face the same, a characteristic in which a dielectric constant or a magnetic permeability in a high frequency region changes due to an electromagnetic field. With an insulator interposed, the dielectric constant or magnetic permeability of the insulator is changed by a direct current or low frequency electromagnetic field applied to the insulator through the ground plane and a plurality of patch plate conductors, so that the directivity of the antenna can be changed. Therefore, a single antenna element can be used as an antenna with a directional characteristic adapted to the radio wave condition, a receiving system resistant to multipath fading can be configured, and since the antenna element is a single unit, space saving and cost reduction can be achieved. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a variable directivity electronically controlled antenna device according to the present invention. FIG. 2 is a plan view of the antenna element in this embodiment. FIG. 3 is a sectional view of a main part of FIG. 4 (a) to 4 (c) are explanatory diagrams showing the change in the orientation of the liquid crystal molecules of the liquid crystal dielectric in this example. FIG. 5 is a characteristic diagram showing a change in the high-frequency relative permittivity of the liquid crystal dielectric. FIG. 6 is a sectional view of a main part of an insulator showing another embodiment of the present invention. FIG. 7 is a configuration diagram of a conventional antenna. 10: antenna element, 11: ground plane 12a-12h: patch plate conductor 13: liquid crystal dielectric (insulator) 18: DC bias control circuit (control means)

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) H01Q 3/00-3/46 H01Q 13/00-13/28 H01Q 21/00-25/04

Claims (1)

(57) [Claims] 1. A ground plane and a plurality of patch plate conductors arranged in parallel in opposition to the ground plane, and interposed between the ground plane and the plurality of patch plate conductors, the permittivity or magnetic permeability in a high-frequency region is controlled by an electromagnetic field. Electronic control, comprising: a changing insulator; and control means for variably controlling the directivity by changing an electromagnetic field distribution applied to the insulator via the ground plane and each patch plate conductor. Antenna device.